A computer model is being developed for arterial blood flow, with especial emphasis at branches, taking into account arbitrary cross-section geometry and entrance effects. It furnishes velocity profiles, wall shearing stresses and axial pressure distribution. It predicts reversal in pressure gradient, separation and backflow of the blood near the outer wall. Atherogenic implications are being studied. Experimental studies on a 30 degrees branch flow apparatus are being made, for validating the model. Backflow effects have been observed by dye streaming, and pressure augmentation by manometer measurements. Velocity profile measurements are in progress and an improved 2-dimensional 60 degrees system is being built for more accurate pressure measurements and for pulsatile flow.